Method and apparatus for pressure butt-welding tubes and the like



Patented NW. 2 1932 UNITED STATES PATENT OFFICE EDWARD F. BEGTRUP, OF JI'IEIRISEYv CITY, NEW JERSEY mop am) arra'an'rus, r03 rnnssunn Burr-wanna TUBES AND THE m 7 Application filed December as, 1930. Serial No. 504,254.

I The invention relates to certain improvements in the pressure butt welding of tubes, bars and similar metal bodies by means of the superheated products of the alumino-thermic reaction, as more particularly pointed out in the following specification, predicated on the accompanying drawing which is a sectional elevation of a mold of novel form for carrying out the invention.

In making alumino-thermio ,pressure butt welds between the ends of tubes, pipes, bars or Slmildi'a metal bodies, the eneral practice has been to dress the ends 0% the bodies flat and square,-abut the ends by means of suitable clamps, and surround the abuttedends 5 poured, the pouring being efiectediby decante t that, when it is completely filled with the by a split mold, usually of cast iron, within which mold there is provided an annular space which completel surrounds the outer peripheriesof the on s of the bodies to be welded. 'llhe mold is provided with a perpendicular pouring gate substantially tanent to the annular mold cavity into which the alumino-thermic reaction products, consisting of superheated slag and metal, are

ing the molten mass from the top oi: the crucible, in order that the slag may enter the mold first and be followed by the metal.

After the mold has been filled with the super-' 0 heated reaction products, there is a transference of heat. units from said products to the ends-of the tubes, bars or other bodies to be welded, which quickly brin these ends to a temperature'suhdcient to e ect butt welding of the bodies, which is then brought about by forcing or pressing the bodies together me-. chemically. The annular space within the.

mold surrounding the ends of the bodies is usually made of such dimensions and capacity su erheated slag and metal, there will be just su%cient heat units available for transfer to the ends of the bodies to be welded to bring the said ends to butt welding temperaturfir The alumino-thermic mixture gener lly employed in this method of welding produces, uponreaction, approximately one-half of its wei ht in metal and one-half of its weight in a umina slag, which translated into volume is one-third metal and two-thirds slag. When these products of the reaction are poured into the mold, the slag enters first and the metal follows and the latter being of higher specific gravity finds its level in the bottom of the annular mold space with the slag filling the up-per portion of the mold cavity or space. .Y When the charge is just suflicient to fill the mold cavity, the metal occupies the lower third thereof and; the slag the u per twothirds. By this construction and isposition of the mold and the bodies to be welded, it

was found that those portions of the said those portions of the bodies surrounded by the slag and it was also noted that the portions of the bodies adjacent the metal, upon completion of theweld, had .a more pronounced outward bulge than the parts surrounded by the slag, a condition particularly completely overcome by the present inven= tion, so that practically perfect'welds may be cated. The fundamental princi le upon bodies adjacent the body of metal in the bottom of the mold did not become ashot as effected between bodies of the character indiwhich the invention is based is. to e ectheating' or the ends of the bodies to be welded by contact with the superheated slag within the mold cavity, which slag is so disposed in the cavity as to completely surround the onclosed ends of the bodies; This result is preferahly effected by means of a mold of the type illustrated in the drawing, in which 2 is the upper section of the mold, 3 the lower section thereof, 4 the annular s ace ormold cavity which surrounds the en s of the tubes or similar bodies 5 to be welded, which ends are enclosed within the mold. The upper mold section is provided with the usual pouring gate 6 and vent 7. The mold cavity in the bottom section of the mold is extended downtill wardly to,provide a recess,'well or sump 8 v of suficient capacity to receive the metal constituent fol? the reaction products indicated at 9, so that the superheated metal will col- 1' lect in this recess or well, learin the ends of the bodies to be welded complete y surrounded by the superheated slag 10.. With this distribution of the alumino-thermic. products, perfect uniformity of welds can be had between the ends of the tubes or other bodies, with no dis roportionate bulge at any point in the perip eries thereof. By this practice, thin walled tubing, as well as alloy tubes,

both ferrous and non-ferrous, may be successfully butt welded.-

This method of butt welding is of especial advantage, because of the fact that the alutie mina slag solidifies at a very high tempera.- ture and has a very low coetlicient of expansion, so that, when the slag completely surrounds the enclosed ends of the bodies to be welded, it is efiective in supporting and maintaining the symmetry of the bodies, especially tubes, which must be heated to substantially melting temperatures to efiect the welding ereof. v,

As stated, the invention is especially eflicacious in makin butt welds between thin walled tubes an various alloy tubes, which could notbe butt welded by the alumino-- thermic method as heretofore practiced.

What I claim is:

' 1. The method of butt-pressure welding tubes, bars like metal bodies, which c0mprises encloslng the ends of the bodies in abutting relation'in a mold, filling the mold cavit about said ends and completely surroun ing said ends'solely with the, mass of superheated sla reaction, while eeping the metal of the reaction away fi'om and at one side of said bodies and pressing the ends of the-bodies together. i v

2. The method of butt-pressure welding tubes, bars and like metal bodies,=whi'chcomprises enclosing the ends of the bodies in abutting relation in a mold, filling themold cavity about said ends and completely sur-' rounding said ends solely with the mass of superheated slag from an alumino-thermic reaction, collecting the metal of said reaction in a separate section of the mold away from and at one-side of said bodies to avoid contact between said metal and the bodies, and press-' the ends of the bodies together. I n testimon whereof ll afiix my signature.

1 nwann 1F. nne'rnme.

l aeeaeie from an alumino-thermio 

